Provided are a carbon dioxide absorbing composition including an ionic material containing a spiro ammonium cation and a method of separating carbon dioxide using the same, and the carbon dioxide absorbing composition of the present disclosure has high thermal and chemical stability and excellent carbon dioxide absorption effect. In addition, the method of separating carbon dioxide using the carbon dioxide absorbing composition is very effective for desorption of carbon dioxide, and is a very economical method since it allows repeated use of the carbon dioxide absorbing composition.

Provided are a carbon dioxide absorbing composition comprising an ionic material comprising a cyclic ammonium cation and a method of separating carbon dioxide using the same, and the carbon dioxide absorbing composition of the present disclosure has high thermal and chemical stability and excellent carbon dioxide absorption effect. In addition, the method of separating carbon dioxide using the carbon dioxide absorbing composition is very effective for desorption of carbon dioxide, and is a very economical method since it allows repeated use of the carbon dioxide absorbing composition.

An absorber of a carbon dioxide capture system according to an embodiment includes: a release region for releasing carbon dioxide from an absorbing liquid supplied from a stripper; and a second gas-liquid contact unit to which carbon dioxide released in the release region is supplied together with exhaust gas discharged from a first gas-liquid contact unit. The absorbing liquid having released the carbon dioxide therefrom in the release region is supplied to the second gas-liquid contact unit by an absorbing liquid supply device. The absorbing liquid having passed through the second gas-liquid contact unit is guided to the first gas-liquid contact unit while bypassing the release region. The second gas-liquid contact unit brings the exhaust gas and the absorbing gas into contact with each other so as to cause the carbon dioxide contained in the exhaust gas to be absorbed in the absorbing liquid.

An improved process for deacidizing a gaseous mixture with reduced overall energy costs is described. The process involves contacting the gaseous mixture with at least one of a vaporizing compound, a vaporized compound, a vaporizing solution of compound and a vaporized solution of compound, and forming a liquid or solid reaction product that can be easily separated from the gaseous mixture.

Amine-based solvents, carbon dioxide capture systems, and methods for improving stability of carbamate during carbon dioxide capture are disclosed herein. The amine-based solvents comprise at least one cyclic amine having a first molecular site that is structurally modified to be protonated and a second molecular site that is structurally modified to hold carbon dioxide as carbamate. The carbon dioxide capture systems comprise at least one gaseous stream comprising carbon dioxide and the amine-based solvent in contact with the at least one gaseous stream. The methods for carbon dioxide capture comprise contacting at least one modified cyclic amine to a gaseous stream comprising carbon dioxide such that the modified at least one cyclic amine chemically reacts with carbon dioxide to form a soluble compound.

In some embodiments, an aqueous composition for removing acid gas components from a process gas includes a first cyclic amine having a substituted carbon atom alpha to an amine atom, and a second cyclic amine having two unsubstituted carbon atoms, wherein each of the unsubstituted carbon atoms is alpha to an amine atom. The composition further includes a molar ratio of the first cyclic amine to the second cyclic amine of about 6:1 to about 2:1.

An aqueous solvent composition is provided, comprising a nucleophilic component having one or more sterically unhindered primary or secondary amine moieties, a Brnsted base component having one or more basic nitrogen moieties, a water-soluble organic solvent, and water. A biphasic composition is provided, comprising one or more carbamate compounds, one or more conjugate acids of Brnsted base, a water-soluble organic solvent, and water. A biphasic CO.sub.2 absorption process is also provided, utilizing the biphasic solvent composition.

The embodiments of the present disclosure relate to a carbon dioxide absorbent containing an ionic material containing a spiro ammonium cation and a hydroxide anion. The carbon dioxide absorbent according to an embodiment contains a hydroxide anion having a small molecular weight and high basicity, such that absorption performance per unit volume of the absorbent may be effectively improved. Further, the carbon dioxide absorbent according to an embodiment is soluble in water and thus may not cause layer separation problems.

A redox flow acid-gas capture system includes an electrochemical cell including a cathode configured to contact a stream including an electroactive species in an inactive state and provide a reduced stream including the electroactive species in an active state, and an anode configured to contact an adduct stream including an adduct of an electroactive species and an acid-gas and provide an oxidized stream including the electroactive species in the inactive state and the acid-gas; an absorber configured to contact the reduced stream and the acid-gas and form the adduct stream including the adduct of the electroactive species and the acid-gas; and at least one of an oxygen stripper unit, or a degasser unit configured to provide a degassed stream including the electroactive species in an inactive state, and an acid-gas stream.

A composition for carbon dioxide (CO2) capture includes 2-aminocyclohexanol, cis-1,2-diaminocyclohexane, meglumine, or combinations thereof. A process of CO.sub.2 capture includes mixing a CO.sub.2-containing gas with the composition. A system includes a component for receiving a gas and the composition, which absorbs CO.sub.2 from the gas. A further composition includes a first amine solvent selected from 2-aminocyclohexanol, cis-1,2-diaminocyclohexane, and meglumine and a second amine solvent independently selected from 2-aminocyclohexanol, cis-1,2-diaminocyclohexane, meglumine, ethyl diethanolamine, dimethylethanolamine, piperidine, 2-amino-2-methyl-1-propanol, and monoethanolamine. A further process includes reacting CO.sub.2 with an amine selected from 2-aminocyclohexanol, cis-1,2-diaminocyclohexane, and meglumine.